Beyond money, trouble with contractors has slowed state regulators working to clean up underground fuel leaks, according to records and interviews with consultants and state officials.

As early as 1995, the watchdog Legislative Audit Council noted DHEC had made more than $200,000 in improper payments to contractors.

And disputes with contractors have helped some jobs drag on for years.

Among them:

In Cherokee County, DHEC paid a contractor $52,000 to clean a state Department of Transportation maintenance yard, then allowed the company to quit in 2005 before the cleanup was completed. The contractor said DHEC didn’t explain the extent of the pollution. Various contractors worked there 14 years, earning about $400,000, before DHEC decided the remaining pollution would clean up on its own.

In Newberry County, a contractor complained his company could not clean up a Department of Transportation site because it found more groundwater pollutants, including solvents, than it bargained for. The contractor billed DHEC $148,000, DOT records show. A second contractor said the first had improperly installed equipment. The pollution was discovered in 1987; the cleanup is not complete.

DHEC also has declared some sites clean, only to learn that pollution remained. The agency said in 1997 that an old store in Hopkins no longer needed cleanup; three years later, regulators found unsafe levels of pollution, records show.